pro(re)gress

The Paypal error 4003 (when receiving PDT) could happen the server is doing too many requests/validations for the same "tx" (transaction id) with a cmd=_notify-synch. Paypal will not send back the data after about 5 requests. Sometimes the error could happen randomly in sandbox. This shouldn't happen in "live".

merchant_return_link=click+here merchant_return_link=return+to+merchant merchant_return_link=* it could happen if: the client browser is clicking the button while not accepting/using/respecting the META tag redirection the autoreturn is set to off in the the merchant account an url rewriting could be a solution